Control of aircraft



- Aug? 1936. E. A. STALKER 2,049,573

CONTROL OF AIRCRAFT Filed March 14, 1956 3 Sheets-Sheet. 1

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4, 1936 E. A. STALKER CONTROL OF AI RCRAFT Filed March 14, 1936 3 Sheets-Sheet 3 lllIL III II f {Jilly i Patented Aug. 4 1936 UNITED STATES PATENT OFFICE My invention relates to the control or aircraft F through aerodynamic means. It contains sub- J ject matter in common with my application Serial No. 757,149, filed December 12, 1934. The objects of my invention are first, to provide means of creating rolling moments through control ofv the boundary layer; second to provide means of creating adequate rolling moments accompanied by proper yawing moments; third to provide means of obtaining proper rolling moments at angles of attack of the wings beyond the normal range. Other objects will appear from the accompanying description drawings. I accomplish the above objects by the devices illustrated in the accompanying drawings in which v Figure 1 is a fragmentary top plan view of the aircraft; I Figure 2 is a fragmentary front elevationpartly in section;

Figure 3 is-a section along the line 3-4 in Figure 1; Figure 4 is section along line 4-4 in Figure Figure 5 is a fragmentary plan view of an alternate but preferred wing;

Figure 7 is a fragmentary section of the wing, taken along line I--'I in Figure 5;

Figure 8 is a section taken at the center of the wing along line 8- -8 in Figure 5; I

Figure 9. is a; fragmentary top plan view of the wing showing the location of the blower along the span;

Figure 10 is an. axial section of the control cylinder;

Figure 11 is a fragmentary top plan view of still another wing;

.Figure 12 is a vertical section along the line "-42 in Figure 11;

Figure 13 is a'fragmentary part section of the aircraft;

Figure 14 is a vertical sectionalong line "-44 in Figure 11; V

Figure 15 is a top plan view of a controlgate;

Figure 16 is avertical elevation of a gate;

Figure 17 is a'fragmentary vertical section of the aircraft to show the relation of the control stick to the control mechanism in the wing.

Similar numerals refer 'to similar parts and Figure 6 is a section along line 6-6 in Figure should be eitherneutral or slightly in the direction of the turn. That is, the rising wing should also have a tendency to advance morerapidly than the declining wing. Ordinary ailerons give.

the reverse action. 5

When the aileron is depressed on one side of the airplane the lift increases and along with it the induced drag which is afuncfion only of the lift and the span. The aileron on the opposite side is raised and the lift is decreased with a re- 10 sultant decrease of induced drag. These drag changes are obviously of the wrong sign and cause an adverse yawing moment. It is one object of this invention to remedy this defect.

Ailerons, as is well known, become ineffective l5 near the angle of maximtm lift of the wing. There is a. very definite ultimate maximum lift for conventional wings due to a change in angle of attack or camber. An ordinaryaileron gives a rolling moment by changing both the angle of 20 attack and camber of the outer portion of the wing. If thewingisalreadyflyin atmaximum lift angle a further mcrease in angle of attack by a. depression of the aileron will not lead to a further increase in lift.

It is known that the ultimate value of the 25 maximum lift for a conventional wing can be increased by an energization of the boundary will merely induce turbulence in the flow in oppo- 40 sition to the pin-pom of boundary energization to reduce it.

Any airdischargedfmmaslotintotheboundary layer must have at least as much energy or velocity as the boundary layer, more if energize- 45 tion is to take 'place. Air of lower energy or velocity when mixed with the boundary layer will serve onlytode-energizethebmmdarylayer sinceafter mixing, the energy or velocity per unit volume will be less.

This application differs from that of Serial No. 757,149 in providing a surface slot in the wing-tip surface instead ofathroughslotandin providing bothsuction and blowing means for surface slots in the central portion of the wing.

,6 in the central portion of the wing leading into the compartment 3 is a rearward directed discharge slot to discharge fluid along the wing surface toward the trailing edge of the wing. The

slots I and 8 leading into the tip compartments.

4 are also discharge slots formed similarly to slot 6. Slots 9 and iii are induction slots primarily and are in communication with the compartments 5 as indicated in the figures.

A duct ll leads into the wing compartment 3 and has the exit II. A suitable blower (not shown) in the fuselage is to be used to force fluid such as air into the compartment 3. This fluid will issue from slot ii and energize the boundary layer so that very large lifting capacity, can be realized from the wing.

To control the lateral or rolling movement of the aircraft a flow to the compartments 4 and 5 is provided for by the ports l3 and H at each wing tip.

In normal straight flight the ports ll are closed by the gates l5 so that there is no flow through theslots 9 and [0- but a discharge through slots 6, I and 8. That is, when both gates We are symmetrically disposed with respect to the longitudinal axis of the aircraft, they do not completely close the ports II.

In executing a 'roll the gates are positioned as shown in Figure 1. The wing tip having slot 8 is to rise and the tip with slot I is to fall. The gate positions permit an outflow through slot 8 to increase the lift and a flow through slot 9 to decrease the lift. Slots 1 and iii are closed to communication with compartment 3 to exclude any flow, which is desirable for the tip movements indicated. If the opposite roll is desired the position of the gates on opposite sides of the aircraft is reversed.

The movements of the gates are controlled through the levers l9, links H and [8, bell cranks I9, and rod 20 which inturn is moved by the bell crank 2|, rod 22 and torque tube 23 rotated by the control stick ll.

I illustrate the preferred form of the wing in Figures 5 to 10. The wing is la and has within similar tip compartments to wing l. The central portion of the wing is divided into two compartments Ia and to. Each of these compartments has a slot in the upper surface. The front slot 8 is a discharge slot while slot 9a is an induction slot.

As shown particularly in Figures 6, 'I and 8, compartment 3a is separated from compartment So by the horizontal wall 25. A central opening 25 accommodates a blower I! rotatable with shaft 28. A suitable means of driving the blower has been described inmy Patent Number 1,913,644 issued J1me 13, 1933. The rotation of the blower induces a flow inward through the slot in. and out the slot 6.

- Itisto benotedthatport llisbelowport so that they communicate with the compartments 3a and 3b, respectively. See figure 6 particularly.

Lateral 'controlis obtained by controlling the flows out the slots I to II. As shown in Figure 5 the gates 29 and 99 are set for a rise of the wing tip having slots 8 and II. That is, the right-hand gates are open so that a flow is induced through Referring to the Figures 1 to 4 particularly, the

slots l0 and 8, the former having an inflow; and the left-hand gates are closed so that there is no communication between slots 1 and 9 and the compartments 3a and 3b.

In the under surface of the wing there are additional ports 3|a leading into the compartments 5. These ports are normally closedby a valve 32a, as shown on the right of Figure 5. When executing a roll, one of the ports is partly open as, for instance, on the left in Figure 5. The valve 32a is rotated in coordinated relation with the gates 29' and 30 and serves to increase the drag of the left wing tip and decrease its'lift. The flow of air out the slot 9 from port 3|a increases the drag of the wing tip. The result is a very powerful lateral control with the adverse yawing moment suppressed to any desired degree. The control is particularly powerful because both suction and blowing are. applied to one wing tip simultaneously with the elimination of the flow from slot 1 and the destruction of the lift by a flow from slot 9.

The mechanism to operate the gates and ailerons lb and lc is illustrated in the figures. A rod 20 interconnects the levers 33 rotatably mounted on suitable bearings at 34. Links 35 and 3S connect the gates to the lever 33. .It will now be clear that a lateral movement of the rod 20 will open and close the ports i3 and M. The gate 30 has fixed to it the lever arm 31 to which is attached universally the aileronrod 38. They attach to the ailerons 'lb and lo. Thus when the gates rotate the ailerons are also rotated. 'If the. operation of the mechanism is traced it will be found that an upward movement of the trailing edge of the aileron lb coincides with anoutward flow through the slot 9 so that both devices decrease the lift of the wing. A similar description applies to aileron lc. A downward movement of the ailerons coincides with lift increasing flows through the tip slots.

Thevalve 32a is controlled by the rod 39a pin connected at one end to gate 30 and at the other to the bell crank a which is pivoted at 40b. Links 380 and 38b extend forward to the valve arm 32c fixed to the valve 32a which is hinged at 32!). It will be apparent then that when the gated! is inhthe fully .closedv position the port or slot Ila in the lower surface of the wing is open.

A cylinder 49 is interposed between the links "a and 98b to introduce a lag in the operation of the valve 32a. with respect to gate 30. A cross section of the cylinder is shown in Figure 10.

The link 394 having the piston 42 at one end connects to the crank 40a. The piston is free to move in one direction but is yieldingly restrained against the opposite movement by the spring 49. When the rod 98a is pushed forward the valve 32a is closed and since rod 38a is made somewhat over-length the spring .43 is slightly compressed after the valve 32a has 'made contact with the beveled edge of the wing port 3la. when 380 ismoved rearward there is some movement of the gates before 32a is rotated. This lag in operation permits the gates 39 to be open into the central compartment 3 while the slots aoaasvs.

andlmrllandlllcmnmunlcatewiththecompartmentslandl-Theslotssuchas andsareseparatedfruneachothersothat thereisnofluwwlfllinthewingfrmntherear' compartmentto the fronhas would be the case becausethesuctionatthefrontofawingis' greaterthanattherear.

Airis'wiizhdrawnfrornthewingthrough the ductlLFlgure li hhytheblower l8.

Fbrlateralconiaolthegatesliaandilaare operated diiierentially withthevalves 32. That is,theportsl3and.llareclosedastheports 3i areopened. 'Ihusatmewlngtipaninward flow through slots and llisinducedbythe fault whileattheothertlpaiiowoutthe slots is and s iscrcatedto'dcstmythe lift.

2 Proper rolling and yawing moments are thus provided.

The valves 32 are controlled by the valve rods alternately in communication with the relative wind through its respective said inlet and with the said' blower means to produce rolling and yawing moments on the aircraft by flows through the slots. 9 a

2. In an aircraft, a wing having a compartment within and an associated slot on each side -of the longitudinal axis of the aircraft. each of 3S whichhavethecylindersllattheirenda- Theactionissimilarto'thatdescribcdinconnection withlfigurefi. 'nmswhen'll ismoved inward there is some movement of the gates beforethevaiveflisrotated. 'lhislaginoperation is desirable to insure that air does not enter the compartments 5 before the ports 14 The mechanism to operate the gates and valves issimilartothatshowninllgurefa. Figure 13 shows a side view of the conia'ol stick 24, torque tube 23 and rod 22. This type of pilot's control is a conventional and well known type.

Atypical gateisshown inliigure's 15am! 16.

Thegatehastwovertieaiwall'sllandllanii isopenonthethirdverticsl'side. Thereare aJsotopandbottomwallsllandilrespectively.

Iprefertheuseofaconventlcnalwingsecsaid slots leading out of its respective compartment and extending spanwise in the upper surface for use in energizing the boundary layer, a blower means normally in communication with both said compartments to induce a flow into said compartments to energize the flow over the wing, a roll inducing device operable at each side of the said axis, and controllable means to operate said roll inducing device at one side of said axis to lower the wing on said side and to direct a flow from said blower means out the surface slot on the same side in coordinated relation while the inflow through the slot on the opposite side is maintained.

3. In an aircraft, a hollow wing having a blowing control-compartment and a suction control compartment at each tip and each com- ;partment having a slot in the upper surface in "than, that is, one having an increasing radius of curvature from the nose'to the trailing edge. I also prefer that the "slots for boundary control have a width of from one-half to two per cent of the chord length although much wider slots can be used.

Slots for blowing rearward should have walls alongthewhmarea sinceblowingoutlqwersurface slotswlllinfluencethedragandliftofawlnmlwlshitunderstood thatfdonotiimit nurinvention touppershrfaceslutsflfll' WhileIhave illustratedapreferred embodiment-ofmyinventlomliwishitunderstoodthat Idonotintendtolimitmyseiftotheseexact commlmication'wlth the compartment interior, said wing being mounted in said aircraft to transmit a yawing torque thereto, a means of blowing arranged for communication with said compartments through their inner ends, and means to control communication to said slots by said meansof blowing to provide at one wing tip an outflow for a blowing slot and an inflow for a suction slot as well as to provide at the opposite wing tip an outflow for the suction slot, said means to control a rolling moment in conjunction with a suitable yawlng moment.

4. In an airplane, a wing' having at all localities thereon the same direction of motion through the air as the aircraft and having at each wing tip a compartment within and upper surface slots in communication with the interiors of said compartments, said surface slots beingtormed with their discharge axes directed more nearly along a perpendicular to the suran outward flow tends to destroy the lift, a means of blowing in-communication with the inner ends of the compartments to cause a flow from said compartments out through said slots, and control means operable to direct a discharge face at the slot than transverse thereto so that.

of air from a preselected slot to provide rolling and yawing moments on .the aircraft,.said slots having widths which are minor fractions of the slot length so as to-be suitable for controlling forms but intend to claim my invention broadly assetforthintheappendedclaims.

Iclaim: I Llnanaircrafhawingasociated witha relative wind and having a substantially fixed relationtotheaircraftinahorlamtalplaneso to exert roll on each sideof said axh iii-communication with 7 a compartment interior, eachwsaidslot being elongated spanwise and leading .out of its respective compartment and having overlapping sides to direct jets rearward along the surface; each said slot-being formed so that astraight line through the slot touching opposite walls of the slot makes an angle less than 30 degrees with the tangent to the wing'section contour at the slot, a second slot on each side of the said axis in the -upper surface leading out of the wing, the said second slots being formed to discharge-chiefiy'upward away from the .wing surface. for-use in destroying the lift by a jet dis.- charge, means of blowing in communication with said compartments and slots to induce Jets out said slots and controllable means to govern simultaneously the flowdifferentially between blowing slots at opposite wing tips, and between said second slots at opposite tips to exert rolling and yawing moments on the aircraft.

6. In an aircraft, in combination a wing having a blowing control compartment and a suction control compartment near each wing tip,-

also a main blowing compartment and a mainsuction compartment, said wing having in its upper surface suction slots in communication with the said: suction compartments and blow-. ing slots-in communication with said blowingcompartments :blower -means to change ,the pressures in said main compartments to cause flows through their slots to energize the boundary'layer on the wing, and controllable means to eifect at one wing tip communication between the main blowing compartment and the control blowing compartment and between the mainrsuction and the control suction compartment while suppressing communication between the. main and controlcompartments at the opposite tip of the wing, and means to provide a-flow out said suction slot at said opposite tip, said combination providing favorably related rolling and yawing moments on the aircraft.

.7. In. an aircraft, in combination, a wing having a main blowing compartment and a main suctioncompartment, also a blowing control compartment and a suctipn control compartment on each side of the longitudinal axis of the aircraft, -a suction slot :and a blowing slot in communication with the main suction and main blowing compartments respectively, said wing also having on each side of said axis suction and blowing slots in the surface respectively incommunication with said suction control and blowing control compartments, a means of blowing in communication with said main suction and main blowing compartments to induce an inflow at the suction slot and an outflow at the discharge slot, controllable means of communica-' EDWARD A. STALKER. 

